* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    color: rgba(255, 255, 255, 0.6);
}
.wrap {
    display: flex;
    justify-content: center;
    align-items: center;
    background: url("img/bg2.jpg") center no-repeat;
    // background-size: length(100vw 100vh);
    background-size: cover;
    height: 100vh;
}
.nav {
    width: 110px;
    // width: 280px;
    height: 820px;
    background: rgba(0, 0, 0, 0.8);
    border-radius: 20px;
    transition: 0.5s;
    .btn {
        width: 60px;
        margin-top: 20px;
        margin-left: 25px;
        display: flex;
        justify-content: space-around;
        //能不能使用伪元素选择器
        .btn-item1 {
            width: 10px;
            height: 10px;
            border-radius: 10px;
            background: #eb5a56;
        }
        
        .btn-item2 {
            width: 10px;
            height: 10px;
            border-radius: 10px;
            background: #f8bc33;
        }
        
        .btn-item3 {
            width: 10px;
            height: 10px;
            border-radius: 10px;
            background: #62cb44;
        }
    }
    .header {
        width: 250px;
        height: 60px;
        margin-left: 25px;
        margin-top: 20px;
        display: flex;
        // overflow: hidden;
        .header-ava {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            border: 4px solid rgba(255, 255, 255, 0.3);
            overflow: hidden;
            img {
                width: 100%;
                margin-top: -5px;
            }
        }
        .header-con {
            margin-left: 20px;
            transition: 0.5s;
            opacity: 0;
            div {
                font-size: 32px;
                font-weight: 500;
            }
        }
    }
    .main {
        // display: flex;
        // flex-direction: column;
        // width: 250px;
        .line {
            width: 60px;
            height: 1px;
            background: rgba(255, 255, 255, 0.6);
            margin: 20px 25px;
            transition: 0.5s;
        }
        .title {
            // text-align: center;
            margin-left: 31px;
        }
        .menu {
            // display: flex;
            // flex-direction: column;
            width: 230px;
            margin-left: 25px;
            margin-top: 20px;
            .item {
                border-radius: 5px;
            }
        }
        .server {
            // display: flex;
            // flex-direction: column;
            width: 60px;
            // width: 230px;
            border-radius: 10px;
            margin-top: 20px;
            margin-left: 25px;
            background: rgba(0, 0, 0, 0.7);
            overflow: hidden;
            transition: 0.5s;
        }
    }
}
.item {
    display: flex;
    align-items: center;
    // position: relative;
    transition: 0.2s;
    // margin-left: 25px;
    .item-tip {
        width: 6px;
        height: 50px;
        background: #eb5a56;
        position: absolute;
        margin-left: -25px;
        border-top-right-radius: 4px;
        border-bottom-right-radius: 4px;
        opacity: 0;
        transition: 0.5s;
    }
    .item-icon {
        width: 60px;
        height: 50px;
        display: flex;
        align-items: center;
        justify-content: center;
        .iconfont {
            font-size: 26px;
        }
    }
    .item-con {
        width: 0px;
        height: 50px;
        display: flex;
        align-items: center;
        justify-content: center;
        transition: 0.5s;
        overflow: hidden;
        left: -20px;
        position: relative;
    }
    .item-r-icon {
        width: 0px;
        // height: 50px;
        transition: 0.5s;
        // justify-content: center;
        // align-items: center;
        opacity: 0;
        .iconfont {
            font-size: 20px;
            color: #62cb44;;
        }
    }
}
.item:hover {
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.1);
    .item-tip {
        opacity: 1;
    }
}
.nav:hover {
    width: 280px;
    .header-con {
        opacity: 1;
    }
    .item-r-icon {
        opacity: 1;
    }
    .item-con {
        width: 140px;
        // display: flex;
        // justify-content: center;
        // align-items: center;
    } 
    .line {
        width: 230px;
    }
    .server {
        width: 230px;
    }
}